settings: Fix incorrect usage of user_settings.
settings: Fix incorrect usage of user_settings.

'corporate_enabled', 'realm_push_notifications_enabled'
and 'realm_digest_emails_enabled' settings are part of
page_params and not user_settings.

This was introduced in 998d7102753e1e2.

eeshangarg/zulip,rht/zulip,kou/zulip,zulip/zulip,andersk/zulip,andersk/zulip,kou/zulip,rht/zulip,zulip/zulip,andersk/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,eeshangarg/zulip,kou/zulip,rht/zulip,zulip/zulip,kou/zulip,andersk/zulip,kou/zulip,zulip/zulip,rht/zulip,eeshangarg/zulip,eeshangarg/zulip,zulip/zulip,kou/zulip,rht/zulip,eeshangarg/zulip,zulip/zulip,rht/zulip,andersk/zulip,andersk/zulip,eeshangarg/zulip,andersk/zulip,rht/zulip